The relationship between cardiac autonomic function and clinical and angiographic characteristics in patients with coronary artery disease

Abstract

Background: A reduction in heart rate variability (HRV) is considered an important indicator of autonomic dysfunction. Objectives: The aims of this study were to evaluate the presence of autonomic dysfunction measured by HRV in patients with coronary artery disease (CAD) and to compare them with normal subjects. Methods: A sample of 52 men (mean age 54±5.39 years) was allocated into three groups: obstructive CAD ≥50% (CAD+ n=18), obstructive CAD <50%, (CAD-n=17) and apparently healthy controls (CG n=17). Heart rate (HR) was measured at rest using a Polar®S810i for 15 min. HRV was analyzed via Shannon entropy (SE) and symbolic analysis (0V and 2ULV), which relate to sympathetic and vagal predominance, respectively. Statistical analysis included the Kruskal-Wallis test and multivariate analysis (p<0.05). Results: The CAD+ group presented lower SE and 2ULV% values and higher 0V% compared to CADand control groups (p<0.05). In the multivariate analysis, the presence of the clinical characteristics such as myocardial infarction and revascularization in the CAD+ group lead to a lower SE and higher 0V compared to the CAD-group. The use of angiotensin converting enzymes led to a higher SE in the CAD-group compared to the CAD+ (p<0.05). Conclusions: In uncomplicated CAD+ patients the patterns of HRV have a lower complexity, a greater sympathetic modulation and a lower parasympathetic modulation compared to CAD-and control groups in supine resting conditions. These results indicate that autonomic heart dysfunction is related to the degree of coronary occlusion and cardiac compromise.

Nonlinear Analysis of Heart Rate Variability: A Comprehensive Review

“…To illustrate this different interpretation, we present below, the works of Guo R et al [38] (2002) and Kunz VC et al [39] (2011). In the first study, the authors compare, using Recurrence quantification analysis (RQA), the pulse morphological changes in 37 inpatients with coronary heart disease and 37 normal subjects.…”

Linear and nonlinear analysis of heart rate variability in coronary disease

“…There are several algorithms of nonlinear analysis for assessing the complexity of heart period, such as approximate entropy [8], sample entropy [8], noise titration [9,10], bispectrum [11], Shannon entropy (SE) [8], symbolic analysis (SA) [7,12] and conditional entropy (CE) [13]. Nonlinear analysis has demonstrated that complexity decreases with age [14,15], heart disease [12,13] and in conditions characterized by an increase of sympathetic modulation [7,8].…”

“…Nonlinear analysis has demonstrated that complexity decreases with age [14,15], heart disease [12,13] and in conditions characterized by an increase of sympathetic modulation [7,8]. In general, nonlinear indexes may indicate a shift in sympathovagal balance, i.e., a decrease in nonlinear indexes could be related to increased sympathetic modulation and decrease in vagal modulation [7,8].…”

Alteration of heart rate variability in patients with coronary artery disease

“…[5] Kunz et al demonstrated that patients with CAD had a lower complexity of HRV, greater sympathetic modulation, and lower parasympathetic modulation. [12] A change in the balance between the sympathetic and the parasympathetic nervous system is associated with increased risk of arrhythmias such as ventricular fibrillation, resulting in sudden death of patients. [13][14][15] These deaths occur in spite of patients being on regular monitored treatment for CAD.…”